1. Field of the Invention
This invention relates generally to surgical instruments, and more specifically to instruments having such as ligating clip appliers adapted to operate and effectors such as multiple-clip cartridges.
2. Discussion of Related Art
Surgical instrument clip appliers commonly include handles that are operable by a user to close a pair of jaws. In the case of clip applier, a ligating clip, removably mounted within the jaws, can be crimped or closed to engage tissue or occlude a body conduit such as a blood vessel. The clip is initially mounted within the jaws when the jaws are in an opened state. When the handles are operated to move the jaws to a closed state, the clip is crimped to achieve ligation. Reopening the jaws permits removal of the clip applier from the ligating clip.
Particularly in a modular clip applier it is always desirable to increase the stability of the handle assembly. With the handles disposed in a common scissors configuration, a single pivot point or fulcrum permits operation of the handles to open and close the jaws. Unfortunately, with a typical elongate configuration, the handles and jaws are spaced a considerable distance from the pivot point or fulcrum, so that the handle assembly tends to be susceptible to misalignment. When jaws become misaligned, clips cannot be closed properly and may even fall from the jaws of the assembly. Thus stability needs to be maintained along the entire travel of the jaws from the opened state to the closed state.
Particularly in a modular system wherein a disposable cartridge is to be removably attached to a non-disposable handle assembly, the attachment system is of particular concern. In the past, attachments have been made solely with a snap fitting at the fulcrum of the handle assembly. A pin carried by the cartridge has been laterally movable by the handle assembly but has been free to float vertically of the handle assembly. Accordingly, the pin has not functioned as part of the attachment system.
Box hinges have been used at the pivot point or fulcrum in an attempt to increase the stability of the handle assembly. These hinges provide larger areas of surface contact but unfortunately these areas are fairly close to the fulcrum and therefore offer very short lever arms for the maintenance of stability.
The cleaning of the handle assembly is always of interest as this is the reusable component of a modular system. While box hinges have been of some value for stability purposes, they present many hidden surfaces which are not susceptible to cleaning. Furthermore, the box hinges have functioned as permanent attachments and have not permitted complete separation of the handles.
Surgeons have commonly used clip appliers in a method called “palming” where the fingers of the surgeon are disposed along the handles distally of the finger rings. This positioning of the hand relative to the handle assembly increases tactile feedback and therefore is often preferred by the surgeon. Where the scissors configuration has included a significant angle along the handles, the surgeon's fingers and thumb have tended to slip along the handles when using this palming method.
In a modular system, the disposable cartridge is typically manufactured with molded plastic components which are not particularly amenable to close tolerances. Especially where complex linkage is involved, the need for plastic parts with closer tolerances can add significantly to manufacturing costs.